1 /*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "BackupHelperDispatcher_native"
18 #include <utils/Log.h>
19
20 #include "JNIHelp.h"
21 #include <android_runtime/AndroidRuntime.h>
22
23 #include <sys/types.h>
24 #include <sys/uio.h>
25 #include <unistd.h>
26
27
28 #define VERSION_1_HEADER 0x01706c48 // 'Hlp'1 little endian
29
30 namespace android
31 {
32
33 struct chunk_header_v1 {
34 int headerSize;
35 int version;
36 int dataSize; // corresponds to Header.chunkSize
37 int nameLength; // not including the NULL terminator, which is not written to the file
38 };
39
40 static jfieldID s_chunkSizeField = 0;
41 static jfieldID s_keyPrefixField = 0;
42
43 static int
readHeader_native(JNIEnv * env,jobject clazz,jobject headerObj,jobject fdObj)44 readHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj)
45 {
46 chunk_header_v1 flattenedHeader;
47 ssize_t amt;
48 String8 keyPrefix;
49 char* buf;
50
51 int fd = jniGetFDFromFileDescriptor(env, fdObj);
52
53 amt = read(fd, &flattenedHeader.headerSize, sizeof(flattenedHeader.headerSize));
54 if (amt != sizeof(flattenedHeader.headerSize)) {
55 return -1;
56 }
57
58 int remainingHeader = flattenedHeader.headerSize - sizeof(flattenedHeader.headerSize);
59
60 if (flattenedHeader.headerSize < (int)sizeof(chunk_header_v1)) {
61 LOGW("Skipping unknown header: %d bytes", flattenedHeader.headerSize);
62 if (remainingHeader > 0) {
63 lseek(fd, remainingHeader, SEEK_CUR);
64 // >0 means skip this chunk
65 return 1;
66 }
67 }
68
69 amt = read(fd, &flattenedHeader.version,
70 sizeof(chunk_header_v1)-sizeof(flattenedHeader.headerSize));
71 if (amt <= 0) {
72 LOGW("Failed reading chunk header");
73 return -1;
74 }
75 remainingHeader -= sizeof(chunk_header_v1)-sizeof(flattenedHeader.headerSize);
76
77 if (flattenedHeader.version != VERSION_1_HEADER) {
78 LOGW("Skipping unknown header version: 0x%08x, %d bytes", flattenedHeader.version,
79 flattenedHeader.headerSize);
80 if (remainingHeader > 0) {
81 lseek(fd, remainingHeader, SEEK_CUR);
82 // >0 means skip this chunk
83 return 1;
84 }
85 }
86
87 #if 0
88 LOGD("chunk header:");
89 LOGD(" headerSize=%d", flattenedHeader.headerSize);
90 LOGD(" version=0x%08x", flattenedHeader.version);
91 LOGD(" dataSize=%d", flattenedHeader.dataSize);
92 LOGD(" nameLength=%d", flattenedHeader.nameLength);
93 #endif
94
95 if (flattenedHeader.dataSize < 0 || flattenedHeader.nameLength < 0 ||
96 remainingHeader < flattenedHeader.nameLength) {
97 LOGW("Malformed V1 header remainingHeader=%d dataSize=%d nameLength=%d", remainingHeader,
98 flattenedHeader.dataSize, flattenedHeader.nameLength);
99 return -1;
100 }
101
102 buf = keyPrefix.lockBuffer(flattenedHeader.nameLength);
103 if (buf == NULL) {
104 LOGW("unable to allocate %d bytes", flattenedHeader.nameLength);
105 return -1;
106 }
107
108 amt = read(fd, buf, flattenedHeader.nameLength);
109 buf[flattenedHeader.nameLength] = 0;
110
111 keyPrefix.unlockBuffer(flattenedHeader.nameLength);
112
113 remainingHeader -= flattenedHeader.nameLength;
114
115 if (remainingHeader > 0) {
116 lseek(fd, remainingHeader, SEEK_CUR);
117 }
118
119 env->SetIntField(headerObj, s_chunkSizeField, flattenedHeader.dataSize);
120 env->SetObjectField(headerObj, s_keyPrefixField, env->NewStringUTF(keyPrefix.string()));
121
122 return 0;
123 }
124
125 static int
skipChunk_native(JNIEnv * env,jobject clazz,jobject fdObj,jint bytesToSkip)126 skipChunk_native(JNIEnv* env, jobject clazz, jobject fdObj, jint bytesToSkip)
127 {
128 int fd = jniGetFDFromFileDescriptor(env, fdObj);
129
130 lseek(fd, bytesToSkip, SEEK_CUR);
131
132 return 0;
133 }
134
135 static int
padding_len(int len)136 padding_len(int len)
137 {
138 len = len % 4;
139 return len == 0 ? len : 4 - len;
140 }
141
142 static int
allocateHeader_native(JNIEnv * env,jobject clazz,jobject headerObj,jobject fdObj)143 allocateHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj)
144 {
145 int pos;
146 jstring nameObj;
147 int nameLength;
148 int namePadding;
149 int headerSize;
150
151 int fd = jniGetFDFromFileDescriptor(env, fdObj);
152
153 nameObj = (jstring)env->GetObjectField(headerObj, s_keyPrefixField);
154
155 nameLength = env->GetStringUTFLength(nameObj);
156 namePadding = padding_len(nameLength);
157
158 headerSize = sizeof(chunk_header_v1) + nameLength + namePadding;
159
160 pos = lseek(fd, 0, SEEK_CUR);
161
162 lseek(fd, headerSize, SEEK_CUR);
163
164 return pos;
165 }
166
167 static int
writeHeader_native(JNIEnv * env,jobject clazz,jobject headerObj,jobject fdObj,jint pos)168 writeHeader_native(JNIEnv* env, jobject clazz, jobject headerObj, jobject fdObj, jint pos)
169 {
170 int err;
171 chunk_header_v1 header;
172 int namePadding;
173 int prevPos;
174 jstring nameObj;
175 const char* buf;
176
177 int fd = jniGetFDFromFileDescriptor(env, fdObj);
178 prevPos = lseek(fd, 0, SEEK_CUR);
179
180 nameObj = (jstring)env->GetObjectField(headerObj, s_keyPrefixField);
181 header.nameLength = env->GetStringUTFLength(nameObj);
182 namePadding = padding_len(header.nameLength);
183
184 header.headerSize = sizeof(chunk_header_v1) + header.nameLength + namePadding;
185 header.version = VERSION_1_HEADER;
186 header.dataSize = prevPos - (pos + header.headerSize);
187
188 lseek(fd, pos, SEEK_SET);
189 err = write(fd, &header, sizeof(chunk_header_v1));
190 if (err != sizeof(chunk_header_v1)) {
191 return errno;
192 }
193
194 buf = env->GetStringUTFChars(nameObj, NULL);
195 err = write(fd, buf, header.nameLength);
196 env->ReleaseStringUTFChars(nameObj, buf);
197 if (err != header.nameLength) {
198 return errno;
199 }
200
201 if (namePadding != 0) {
202 int zero = 0;
203 err = write(fd, &zero, namePadding);
204 if (err != namePadding) {
205 return errno;
206 }
207 }
208
209 lseek(fd, prevPos, SEEK_SET);
210 return 0;
211 }
212
213 static const JNINativeMethod g_methods[] = {
214 { "readHeader_native",
215 "(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;)I",
216 (void*)readHeader_native },
217 { "skipChunk_native",
218 "(Ljava/io/FileDescriptor;I)I",
219 (void*)skipChunk_native },
220 { "allocateHeader_native",
221 "(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;)I",
222 (void*)allocateHeader_native },
223 { "writeHeader_native",
224 "(Landroid/app/backup/BackupHelperDispatcher$Header;Ljava/io/FileDescriptor;I)I",
225 (void*)writeHeader_native },
226 };
227
register_android_backup_BackupHelperDispatcher(JNIEnv * env)228 int register_android_backup_BackupHelperDispatcher(JNIEnv* env)
229 {
230 jclass clazz = env->FindClass("android/app/backup/BackupHelperDispatcher$Header");
231 LOG_FATAL_IF(clazz == NULL,
232 "Unable to find class android.app.backup.BackupHelperDispatcher.Header");
233 s_chunkSizeField = env->GetFieldID(clazz, "chunkSize", "I");
234 LOG_FATAL_IF(s_chunkSizeField == NULL,
235 "Unable to find chunkSize field in android.app.backup.BackupHelperDispatcher.Header");
236 s_keyPrefixField = env->GetFieldID(clazz, "keyPrefix", "Ljava/lang/String;");
237 LOG_FATAL_IF(s_keyPrefixField == NULL,
238 "Unable to find keyPrefix field in android.app.backup.BackupHelperDispatcher.Header");
239
240 return AndroidRuntime::registerNativeMethods(env, "android/app/backup/BackupHelperDispatcher",
241 g_methods, NELEM(g_methods));
242 }
243
244 }
245